FORT WORTH, Texas — American Airlines, fresh out of bankruptcy and newly merged with US Airways, said Thursday that it will buy 90 new regional jets from Brazil’s Embraer S.A. and Canada’s Bombardier Inc. and use them to replace smaller, less fuel-efficient planes.

Kenji Hashimoto, American senior vice president of regional carriers, said the new planes will reduce operating costs and allow for first-class cabins, economy seats with more legroom that the airline sells for a premium and in-flight Internet service.

Financial terms were not disclosed. The Embraer planes carry a total sticker price of about $2.5 billion, although airlines routinely get discounts.

The airplane order was in the works long before this week’s closure of American’s merger with US Airways, which made it the world’s biggest airline. In a regulatory filing Thursday, the new American Airlines Group said that including the new Embraer and Bombardier firm orders, it has committed $22.5 billion for new planes and engines.

American’s last big order was in 2011, for 460 planes from Boeing Co. and Airbus.

Deliveries from Bombardier are expected to begin next spring, and the first Embraer planes are scheduled to arrive in early 2015.